Investigation of Acoustic Halos using Multi-Height SDO Observations
Abstract
The interpretation of acoustic waves surrounding active regions has been a challenging task since the influence of magnetic field on the incident waves is not fully understood. As a result, structure and dynamics of active regions beneath the surface show significant uncertainties. Recent numerical simulations and helioseismic measurements in active regions have demonstrated that the key to the understanding of these complex processes requires a synergy between models and helioseismic inferences from observations. In this context, using data from Helioseismic Magnetic Imager and Atmospheric Imaging Assembly instruments on board the Solar Dynamics Observatory, we characterize the spatio-temporal power distribution around active regions as a function of the height in the solar atmosphere. We find power enhancements (acoustic halos) occur above the acoustic cutoff frequency and extends up to 10 mHz in HMI Doppler and AIA 170 nm observations and are strong functions of magnetic field and their inclination angle. We also examine the relative phases and cross-coherence spectra and find different wave characteristics at different heights.
- Publication:
-
Catalyzing Solar Connections
- Pub Date:
- November 2018
- Bibcode:
- 2018csc..confE.130T